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visits member for 4 years, 7 months
seen Jul 1 at 22:04

Started programming on a ZX spectrum in the 80's and have moved through Assembly, Turbo Pascal, C++, C#, Fortran. My main area of focus is engineering and scientific computing like numerical methods and 3D graphics.


May
19
comment Area Moment of Inertia about y axis of i Beam
Except the $(b\tau)(.5h_1+.5\tau)$ term of the op isn't needed.
May
19
answered Area Moment of Inertia about y axis of i Beam
May
19
comment Area Moment of Inertia about y axis of i Beam
For $I_y$ all distances to centroids are zero since you can split this shape up to three rectangles. Top, middle and bottom. All three have centroids along the y axis.
May
19
answered Maximum range of projectile from elevation, simply?
May
19
comment Calculating the Precession
"Precession" is not a force (as shown above), but a torque. Actually it is neither as precession is a change in orientation about the first euler angle. Precession, Nutation, Spin being the three euler angles.
May
19
comment In which direction does mud fly off a moving bike's tire & why?
@CarlWitthoft the acceleration vector is $$\begin{bmatrix} \dot{v}_x \\ \dot{v}_y \end{bmatrix} = \begin{bmatrix} -\frac{v^2}{r}\sin\theta+\dot{v} (1-\cos\theta) \\ \frac{v^2}{r}\cos\theta-\dot{v} \sin\theta \end{bmatrix}$$ Take the magnitude and see that is is constant when the bike is not accelerating $\dot{v}=0$, with $\| a \| = \frac{v^2}{r}$.
May
19
comment In which direction does mud fly off a moving bike's tire & why?
You are confusing the fact that the mud that is most likely to come off (loose mud) will come off first, and the mud that is embedded in the treads will stay stuck for far longer. The riders jersey is there catch only the mud from that location. Mud flung from the top will not land on the rider.
May
19
answered In which direction does mud fly off a moving bike's tire & why?
May
19
answered Instantaneous acceleration vector toward the concave side of a curved path
May
18
comment How can I relate linear and angular motion using a single formula?
Actually the op doesn't want a ratio of velocities. The op wants a single (fundamental) equation relating linear and angular quantities.
May
18
comment How can I relate linear and angular motion using a single formula?
You suppose. I still don't know, velocity at which point? Is the velocity of the force application point important to the op? Is the center of rotation point important to the op. If you have a particular situation you have doubts about you can ask your own question so that others have a chance or respond. Note that you shouldn't ask a "Check my work" question, rather you should ask a "How do I approach this situation/concept".
May
17
comment How can I relate linear and angular motion using a single formula?
Are you looking at the same thing exactly? The op question was not clear of what ratio was requested.
May
15
comment Solve $a(t) = g - \beta v(t)$ for $t$
Yes, you direct integration. See answer below:
May
15
answered Solve $a(t) = g - \beta v(t)$ for $t$
May
14
revised Notation of vectors
added 9 characters in body
May
13
answered Notation of vectors
May
13
comment Is tension always constant throughout a rope of mass in equilibrium?
Is there a fulcrum in the middle of the stick? Maybe a sketch can help clarify things.
May
13
comment Angular momentum with respect to the centre of mass
$I_{cm}$ is the mass moment of inertia tensor. It is defined as $$I_{cm} = \begin{pmatrix} I_{xx} & I_{xy} & I_{xz} \\ I_{xy} & I_{yy} & I_{yz} \\ I_{xz} & I_{yz} & I_{zz} \end{pmatrix}$$ (See farside.ph.utexas.edu/teaching/336k/Newtonhtml/node64.html). It contains the components of inertia for each axis in the diagonal, and cross terms on the off diagonal. As the body rotates (with a 3×3 rotation matrix $E$) the components of $I_{cm}$ change also. This is done with $$I_{cm} = E I_{\rm body} E^\top$$.
May
13
revised Angular momentum with respect to the centre of mass
added 1 character in body
May
12
revised Angular momentum with respect to the centre of mass
added 116 characters in body